MH Bulb Questions

Beverly · #1 02-16-2004, 05:33 PM

I have a 175w 6500k MH bulb over my 42g reef that's been set up for almost a year now. I seem to remember that the bulbs should be changed annually. Is this correct? If not, how often do you folks change your bulbs?

Also, I'm thinking of changing it to a 175w 10,000k bulb. Can I do that without changing the ballast? Does anyone have pics of tanks that compare 6500k and 10,000k bulbs so I can see what my tank might look like?

TIA

whaase · #2 02-16-2004, 06:37 PM

These a are 250w comparisons, but it does have the Iwasaki 6500k..

http://reefcentral.com/forums/showth...hreadid=254667

Walter

Delphinus · #3 02-16-2004, 06:38 PM

Yearly is probably best.

You might not need to change your ballast but 10000K's do run better on pulse-start ballasts (ANSI-M137, in your case you are likely using a probe-start or an ANSI-M57).

That said, I'm running 10000K's on M57's. You should be able to get away with it, just be wary that the bulbs may be slow to start. They are a bit sluggish on the starts for me, but it's something I can live with. I'll probably eventually switch my ballasts but I'm in no real rush.

The colour of the 10000K's is a little whiter. I don't really have any comparison pictures but think of it as the difference between a warm-white and a cool-white on a fluorescent bulb. I dunno .. I like 'em. Hard to say what people will like, it varies with taste.

TNTCanada · #4 02-17-2004, 12:01 AM

Here is a good link to try.

http://metricksystem.com/chris/250wcolour/

StirCrazy · #5 02-17-2004, 02:02 AM

I personaly think the yearly changing bulbs sugestion is a myth started by fish stores to increas sales on consumables. the best indacater is a light meter but you would have to have that from day 1 for a comparason.

here is my rational on this.

an average MH bulb has a rated life of 8800 hours or higher (this translates to 2.4 years at 10 hours a day) and at this life span most only have a output drop of 30% (some lower some higher) but 80% of this drop is with in the first 1.5 years. so after 1.5 years your intensity has dropped up to 25% but the bulb is still working good and will only drop another 5% over then next year. I know from my testing after 2 years my AB still puts out more PAR than all the new SA bulbs I got to test so should I change it out just because some one said after 1 year to change it?

Also ther eis the 6 month VHO recomendation, well mine is going on two years and looks almost like it needs changing but that was only in the last 3 months, also remember I was overdriving my VHO by 15% . I think on a workhorse or comprable electronic ballast there is no reason a VHO shouldent last 1.5 to 2 years.

so to answer your questing should you change it after 1 year.... well do you want to change it? it sounds like you do.. and if you desire a more whiter look then by all means change it. maybe spend 30 bucks on a little lux meter at the same time and do a measurment from 12" away.. then do the same measurment every month to see the drop. you will fine that the major part of the output decrease happens in the first 6 months and then the rate that it drops slows down.

Steve